## Software

# ABINIT

ABINIT is a suite of programs for materials science, which implements density functional theory, using a plane wave basis set and pseudopotentials, to compute the electronic density and derived properties of materials ranging from molecules to surfaces to solids. It implements density functional theory by solving the Kohn–Sham equations describing the electrons in a material, expanded in a plane wave basis set and using a self-consistent conjugate gradient method to determine the energy minimum. Computational efficiency is achieved through the use of fast Fourier transforms, and pseudopotentials to describe core electrons. As an alternative to standard norm-conserving pseudopotentials, the projector augmented-wave method may be used. In addition to total energy, forces and stresses are also calculated so that geometry optimizations and ab initio molecular dynamics may be carried out. Materials that can be treated by ABINIT include insulators, metals, and magnetically ordered systems including Mott-Hubbard insulators.

# Crispy

Crispy is a modern graphical user interface to simulate core-level spectra using semi-empirical multiplet approaches.

# GROMACS

GROMACS (GROningen MAchine for Chemical Simulations) is a molecular dynamics and energy minimization package mainly designed to simulate the Newtonian equations of motion for systems with hundreds to millions of particles, typically of proteins, lipids and nucleic acids. GROMACS can run on CPUs and GPUs.

# OCEAN

OCEAN is a versatile package for performing first-principles calculations of core edge spectroscopy. The many-body method is based on ground-state density-functional theory (DFT) and uses the Bethe-Salpeter equation. OCEAN utilizes the programs ABINIT or QuantumESPRESSO for ground-state DFT portion of the calculations. OCEAN is capable of producing various spectra including X-ray absorption near-edge spectra (XANES), X-ray emission spectra (XES), and non-resonant inelastic X-ray scatter (NRIXS or XRS). OCEAN is the result of collaboration between the Rehr group at the University of Washington and Eric Shirley at the National Institute of Standards and Technology (USA).

# PyMca

X-ray Fluorescence Toolkit (visualization and analysis of energy-dispersive X-ray fluorescence data). . The program allows both interactive and batch processing of large data sets and is particularly well suited for X-ray imaging. Its implementation of a complete description of the M shell is particularly helpful for analysis of data collected at low energies. It features, among many other things, the fundamental parameters method

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